The present disclosure relates to medical devices, systems, and methods. In particular, the present disclosure relates to guidewires used in micropuncture sets and many medical procedures.
Many minimally invasive medical procedures rely on catheters and other similar devices introduced and advanced through the vasculature or other bodily lumens. In many cases, such devices are advanced over a guidewire that has been navigated through the vasculature or bodily lumen. Often, the guidewire itself has been introduced first through an introducer needle puncturing tissue and accessing the vasculature or other bodily lumen and then through the vasculature or bodily lumen. The guidewire may then be advanced and navigated toward a target region.
In some medical procedures, small diameter or micropuncture guidewires may be used. For example, regular guidewires may have a diameter of about 0.035″ while micropuncture guidewires may have a diameter of 0.018″. Current micropuncture guidewires may be less than ideal in at least some cases. For example, many micropuncture guidewires may encounter a high degree of friction as they are advanced through the lumen of a small gauge introducer needle. Due to the friction, the operator of the guidewire may lose much tactile feedback. It may therefore be difficult for the operator to discern resistance from the guidewire versus resistance from the micropuncture guidewire encountering plaque or other obstructions in the vasculature or bodily lumen. In some cases, the operator may mistake resistance from plaque or the guidewire abutting the wall of the vessel as resistance from the needle, apply excessive forward force to the guidewire, and inadvertently puncture or dissect the wall of a blood vessel with the guidewire tip. Micropuncture guidewires also may have a smaller diameter than standard guidewires. Therefore, the force exerted by the tip of micropuncture guidewires can be concentrated on a smaller area, which may increase the likelihood of perforating, puncturing, or otherwise causing trauma to tissue. An additional risk of using currently available micropuncture sets may be that after removing the micropuncture needle, in order to enlarge the entry hole into the vessel or body lumen, two coaxial dilators, an inner one with a 0.018″ inner diameter and an outer one with a 0.035″ inner diameter, are typically introduced over the micropuncture guidewire. The inner dilator may then be removed together with the 0.018″ guidewire thus leaving in place a 0.035″ inner diameter dilator. The remaining outer dilator can allow the introduction of a larger 0.035″ guidewire, which must successfully re-cross the segment of the vessel or body cavity which had been previously crossed with the initially introduced 0.018″ guidewire. The attempted re-crossing may pose an additional injury threat and it may be difficult or even impossible to successfully re-cross the vessel or body cavity. There are therefore needs for improved micropuncture guidewires to overcome such disadvantages.
References that may be of interest may include U.S. Pat. Nos. 7,824,345, 7,169,118, 5,507,729, 5,368,049, 5,282,478, 5,133,364, 5,060,660, 4,991,602, and 4,796,642 and U.S. Pub. Nos. 2011/0071435 and 2009/0187147. Many of these references show guidewires and extensions with the same diameter and describe nothing specifying or implying the need for or rationale for different diameter guidewires and extensions. Some of these references also specify that guidewires and their extensions be of the same diameter.